In a system for electronic commerce through the Internet, it is known that there is a case in which many users concurrently access the system within a short period of time. With access congestion, processing of a server and a network device cannot keep up with the increased accesses, which causes a problem that orders from users cannot be processed. In order to avoid this situation, it is known that, for example, the number of accesses at peak is estimated in advance, and a hardware and network circuit lines that can process accesses at peak are prepared. Further, there is a known system that can increase of the number of servers autoatically so as to scale out, depending on the load imposed (for example, Patent Literature 1).